This invention relates to a touchpad apparatus for use with a portable electronic device. It is particularly suitable for use in a portable communication device such as a portable telephone or wireless computer.
Portable telephones generally require a keypad so that a user can enter information, such as a telephone number to be dialed. However, with the ever increasing integration of advanced data facilities into portable telephones, there is often a need to provide a more advanced keypad than a simple numeric type. For instance, with the increasing use of mobile devices to access the Internet, it is desirable to provide some means of cursor control, such as is provided by a mouse or trackball in a PC environment.
With increases in data rates possible, and hence increases in the amount of data receivable by portable telephones, such telephones are increasingly being used in data browsing activities. It is convenient to offer a larger display to enable such received data to be comfortably and easily viewed by the user.
Both these requirements, of more advanced keypads and larger displays, directly conflict with consumer demands for smaller portable telephones.
One attempt to solve this problem was the telephone jointly developed by Alcatel® and Sharp®. The telephone was marketed by each company under the names OneTouch Com and MC-G1 respectively. The telephone 100 is shown at FIG. 1, and comprises many of the features normally associated with portable telephones: antenna 110, loudspeaker 120, display 130, microphone 140, and control keys 150. The notable difference between this telephone and previous portable telephones is the absence of a numeric keypad for entering telephone numbers.
This function is achieved through the provision of a touchscreen which is integrated with the display 130. In order to access the touchscreen, the rotating protective cover 160 must be opened (see FIG. 2) to expose the touchscreen surface, and allow the user to input commands and data using a stylus.
In normal use, when the cover 160 is closed, the display 130 can be seen through a transparent portion in the cover. However, in order to access any of the advanced functions of the telephone, the cover must be opened, the stylus must be removed from its holder in the telephone, and the user must operate the touchscreen to choose the option(s) he requires. No input via the touchscreen is possible with the protective cover in place.
The touchscreen in this telephone is of the resistive type. The operation of such a touchscreen will be well known to the skilled man, and so is not described in any detail here. It is sufficient to know that the display comprises a relatively large glass element, which is why the rotating cover 160 is necessary in order to protect the touchscreen and display from inadvertent damage.
One drawback with such a touchscreen system is that when entering data, the user obscures the display with his own hand.